• Journal of applied mathematics & informatics
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• v.34 no.1_2
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• pp.75-84
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• 2016

The objective of this work is to perform a geometric analysis of the net present value (NPV) and Internal Rate of Return (IRR), defining analytics and in verifying the relationship between geometric properties of such functions. For this simulation, was used the values of the cash flows for each period identical and equal to US$ 200.00 cash, the initial investment US$ 1,000.00 and investments of each identical and equal to US$ 50.00 period. In addition, the discount rate and time were considered a maximum of 2 years (24 months) at a rate between 0 and 100%. The geometric analysis of the characteristics obtained from the expressions of the Net Present Value and Internal Rate of Return possible to observe that besides the analytical dependence between these quantities , the geometric relationships are relevant when studied in relation to the zero NPV and expressed a great contribution the sense of a broad vision for the administrator in the analysis of analytical variables that in uences the balance sheet of the company.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.52-65
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• 2016

The electronic toll collection system(ETCS), is globally used in about 40 countries. In Korea, the Korea Expressway Corporation led the nationwide introduction of the ETC system in 2007 under the brand name of the Hi-pass. Since then, Hi-pass, with its rate of average daily use reaching about 70%, has become an essential facility in Korean expressways. To identify users' perception on Hi-pass (satisfaction, preference, etc.), this study conducted a Modified Importance-Performance Analysis (M-IPA). With this, this study attempted to identify the kind of efforts necessary to enhance current Hi-pass users' convenience and satisfaction. According to the result of M-IPA, the items including "non-stop payment" and "toll discount" are identified as key items that require further improvement. For improvement in the "non-stop payment" item, operations of Hi-pass toll booths appropriate for the demand for Hi-pass use and the selection of Hi-pass booths' locations in consideration of entry and exit lanes need to be improved. In addition, with regard to the "toll discount" item, although toll discount is currently provided to Hi-pass users, thus, PR thereof will have to be strengthened. It is expected that this study will be used as basic data to devise methods of enhancing Hi-pass usage through improvement of Hi-pass users' satisfaction.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.275-287
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• 2016

This study attempts to estimate the benefits of using water ensuing from the Chilgap multipurpose reservoir for environmental improvement. The contingent valuation method (CVM) was used to elicit the willingness to pay (WTP) for providing environmental improvement water from the Chilgap reservoir to Daechi-stream and Ji-stream. The DCDB (double-bound dichotomous choice) survey method was used to collect data for the analysis. Due to the usually high cost of increasing the sample size, the use of follow-up questions was implemented as an inexpensive method of improving the efficiency of the estimation. A spike model was used in this study because a number of respondents showed zero WTP. The spike model can be estimated as easily as the conventional model. Results show that the average annual household's WTP is 4,516 won using the conventional model and 8,644 won using the spike model. Applying the estimated average annual household's WTP to the Chungnam and Daejeon regional levels, the benefits of environmental improvement water from the Chilgap reservoir is estimated at 11.9 billion won per year. The temporal benefits of providing water for environmental improvement, for a 50-year period at a 6.0% discount rate, is estimated at about 190 billion won in the Chungnam and Daejeon areas. These results could be useful especially when the government tries to determine an appropriate level of investment and to make a policy related to providing environmental improvement water.

• The Journal of Industrial Distribution & Business
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• v.14 no.9
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• pp.21-30
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• 2023

Purpose: Focusing on the role of the special contract to collaborate the supply chain operations, this study investigates how the revenue sharing contract affects the performance of Vendor Managed Inventory (VMI). Research design, data, and methodology: The optimization model is formulated to represent two stage supply chain system where the supplier and retailer manage the operations to maximize their own profits. Three supply chain models including the traditional system, VMI, and VMI with revenue sharing contract are compared in the numerical examples. Results: According to the numerical analysis, the entire supply chain system has greater profit under VMI than the traditional system, while VMI alone sacrifices the supplier's profit. With the proper sets of revenue share ratio and wholesale price discount rate, VMI with revenue sharing contract results in the increased profit for both supplier and retailer compared with VMI alone as well as the traditional system. Conclusions: The numerical examples imply that VMI, when it is combined with the revenue sharing contract, can be the effective collaboration program that satisfies every supply chain member. To make VMI with revenue sharing contract to be fair to all supply chain members, they need to agree on the appropriate contract content.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.101-105
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• 2016

The number of deaths is often measured to monitor the population health status and priority of health problems. However, number of years of life lost (YLL) is a more appropriate indicator in some cases. We have calculated the YLL of adult cancers and its trend over the past few years in Yazd to provide planners with baseline data. Data obtained from death registration system were used to calculate the YLL, based on each individual's age at death, and the standardized expected YLL method was applied with a discount rate of 0.03, an age weight of 0.04, and a correction factor of 0.165. All data were analyzed and prepared in Epi6 and Excel 2007. A total of 3,850 death records were analyzed. Some 550 patients in Yazd province aged ${\geq}20$ die annually due to cancer (male: female ratio 1.3). The average ages at death in lung, CNS, breast cancer and leukemia cases were 68.5, 59, 58.7 and 61, respectively. The age group of 40-59 with 21 % had the highest cancer mortality percentage. Premature cancer deaths have caused 40,753 YLL (5,823 YLL annually). Females lose on average more life years to cancer than do men (11.6 vs 9.8 years). Lung cancer (12.1%), CNS tumors (11.7%) and leukemia (11.4 %) were the leading causes terms of YLL due to all cancers in both sexes. From 2004 to 2010, cancer-caused YLL as a fraction of all YLL increased from 12.8 to 15.2 %. This study can help in the assessment of health care needs and prioritization. Cancer is the major cause of deaths and the trend is increasing. The use of YLLs is a better index for measurement of premature mortality for ranking of diseases than is death counts. Longer periods of observation will make these trends more robust and will help to evaluate and develop, better public health interventions.

• Journal of Korean Society of Rural Planning
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• v.18 no.3
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• pp.25-41
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• 2012

The purpose of this study is to quantitatively analyze the social welfare value given to the designated rural settlement zone by the resident-participated site unit plan that the City of Cheongju is newly attempting to draft. Firstly, the costs and benefits from the site unit planning were estimated. Secondly, through literature review especially focussed on the benefit and cost estimation, on-site questionnaire was designed, and then sample residents of the qualifying sites were asked about their willingness to pay, which could make it possible to estimate the monetary value of its benefits by the contingent valuation method (CVM). Finally, the present value of net benefits (PVNB) was estimated through the derived costs and benefits. As a result of analysis, firstly, the present value of net benefits (PVNB) was found to be 7,641 billion won, which indicated that the implementation of district-unit plan would be able to cause sufficient social welfare value for the effected residents. Secondly, in examining the result of individual average amount for willingness to pay through the CVM, the area that benefited the most was found to be the road improvement. Thirdly, as a result of sensitivity analysis, the parameter with the most effects was the discount rate, which suggested that, in carrying out public projects, excessive market interest rates would not be appropriate.

• Journal of Preventive Medicine and Public Health
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• v.55 no.1
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• pp.10-18
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• 2022

Disability-adjusted life-year (DALY) estimates may vary according to factors such as the standard life expectancy, age weighting, time preference and discount rate, calculation of disability weights, and selection of the estimation method. DALY estimation methods are divided into the following 3 approaches: the incidence-based approach, the pure prevalence-based approach, and the hybrid approach. These 3 DALY estimation approaches each reflect different perspectives on the burden of disease using unique characteristics, based on which the selection of a suitable approach may vary by the purpose of the study. The Global Burden of Disease studies, which previously estimated DALYs using the incidence-based approach, switched to using the hybrid approach in 2010, while the National Burden of Disease studies in Korea still mainly apply the incidence-based approach. In order to increase comparability with other international burden of disease studies, more DALY studies using the prevalence-based approach need to be conducted in Korea. However, with the limitations of the hybrid approach in mind, it is necessary to conduct more research using a disease classification system suitable for Korea. Furthermore, more detailed and valid data sources should be established before conducting studies using a broader variety of DALY estimation approaches. This review study will help researchers on burden of disease use an appropriate DALY estimation approach and will contribute to enhancing researchers' ability to critically interpret burden of disease studies.

• Ocean and Polar Research
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• v.40 no.4
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• pp.237-247
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• 2018

This study aims to estimate optimal harvests, fishing efforts, and stock levels of hairtail harvested by the large pair bottom trawl, the large otter trawl, the large purse seine, the offshore long line, and the offshore angling fisheries by using the surplus production models and the current value Hamiltonian method. Processes of this study are as follows. First of all, this study estimates the standardized fishing efforts regarding the harvesting of the hairtail by the above five fishing gears based on the general linear model developed by Gavaris. Secondly, this study estimates environmental carrying capacity (k), intrinsic growth rate (r), and catchability coefficient (q) by applying the Clarke Yoshimoto Pooley (CY&P) model among various surplus production models. Thirdly, this study estimates the optimal harvests, fishing efforts, and stock levels regarding the hairtail by the current value Hamiltonian method, including the average landing price, the average unit cost, and the social discount rate. Finally, this study attempts a sensitivity analysis to figure out changes in optimal harvests, fishing efforts, and stock levels due to changes in the average landing price and the average unit cost. As results induced by the current value Hamiltonian method, the optimal harvests, fishing efforts, and stock levels regarding the hairtail caught by several fishing gears were estimated as 33,133 tons, 901,080 horse power, and 79,877 tons, respectively. In addition, from the results of the sensitivity analysis, first of all, if the average landing price of the hairtail constantly increases, the optimal harvests of it increase at a decreasing rate, and then harvests finally slightly decrease as a result of decreases in stock levels. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts decreases, but optimal stock levels increase. Optimal harvests start climbing and then decrease continuously due to increases in the average unit cost. In summary, this study suggests that the optimal harvests (33,133 tons) were larger than actual harvests (25,133 tons), but the optimal fishing efforts (901,080 horse power) were much less than estimated standardized fishing efforts (1,277,284 horse power), corresponding to the average of the recent three years (2014-2016). This result implies that the hairtail has been inefficiently harvested and recently overfished due to excessive fishing efforts. Efficient management and conservation policies on stock levels need to be urgently implemented. Some appropriate strategies would be to include the hairtail in the Korean TAC species or to extend the closed fishing season for this species.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.799-805
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• 2016

Background: There is no standard treatment for patients with platinum-resistant or refractory epithelial ovarian cancer. Single agent chemotherapies have evidence of more efficacy and less toxicity than combination therapy. Most are very expensive, with appreciable toxicity and minimal survival. Since it is difficult to make comparison between outcomes, economic analysis of single-agent chemotherapy regimens and best supportive care may help to make decisions about an appropriate management for the affected patients. Objective: To evaluate the cost effectiveness of second-line chemotherapy compared with best supportive care for patients with platinum-resistant or refractory epithelial ovarian cancer. Materials and Methods: A Markov model was used to estimate the effectiveness and total costs associated with treatments. The hypothetical patient population comprised women aged 55 with platinum-resistant or refractory epithelial ovarian cancer. Four types of alternative treatment options were evaluated: 1) gemcitabine followed by BSC; 2) pegylated liposomal doxorubicin (PLD) followed by BSC; 3) gemcitabine followed by topotecan; and 4) PLD followed by topotecan. Baseline comparator of alternative treatments was BSC. Time horizon of the analysis was 2 years. Health care provider perspective and 3% discount rate were used to determine the costs of medical treatment in this study. Quality-adjusted life-years (QALY) were used to measure the treatment effectiveness. Treatment effectiveness data were derived from the literature. Costs were calculated from unit cost treatment of epithelial ovarian cancer patients at various stages of disease in King Chulalongkorn Memorial Hospital (KCMH) in the year 2011. Parameter uncertainty was tested in probabilistic sensitivity analysis by using Monte Carlo simulation. One-way sensitivity analysis was used to explore each variable's impact on the uncertainty of the results. Results: Approximated life expectancy of best supportive care was 0.182 years and its total cost was 26,862 Baht. All four alternative treatments increased life expectancy. Life expectancy of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 0.510, 0.513, 0.566, and 0.570 years, respectively. The total cost of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 113,000, 124,302, 139,788 and 151,135 Baht, respectively. PLD followed by topotecan had the highest expected quality-adjusted life-years but was the most expensive of all the above strategies. The incremental cost-effectiveness ratios (ICER) of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 344,643, 385,322, 385,856, and 420,299 Baht, respectively. Conclusions: All of the second-line chemotherapy strategies showed certain benefits due to an increased life-year gained compared with best supportive care. Moreover, gemcitabine as second-line chemotherapy followed by best supportive care in progressive disease case was likely to be more effective strategy with less cost from health care provider perspective. Gemcitabine was the most cost-effective treatment among all four alternative treatments. ICER is only an economic factor. Treatment decisions should be based on the patient benefit.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.120-129
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• 2016

The user cost is an important analysis item which should be considered together with life-cycle of facility, administrator cost and discount rate in LCCA for efficient asset management of SOC facilities. Especially, a significant delay cost occurs often for users in the road field due to a work zone for cleaning and maintenance, and in such case, the administrator should consider the administrator cost as well as the user cost for more rational decision making. However, the user cost has not been considered in most decision making steps until recently and relevant studies also have not been carried out actively. In this study, the methodology to estimate the user cost and delay cost required in the decision making step using the traffic flow model and the direct benefit estimation model in the traffic facility investment evaluation guideline is suggested. And, the traffic flow model was estimated on 4 national highway sections where maintenance was actually carried out in 2014 using VISSIM and, the user cost and the delay cost were estimated based on the suggested methodology. The analysis result showed that the average user cost of $17,569,000KRW/km{\times}day$ occurred on Section A with approximately 30,000 AADT before a work zone occurred, and in case the first lane was blocked for maintenance, the delay cost of $10,193,000KRW/km{\times}day$ (158%) on average occurred additionally. The delay cost of $1,507,000KRW/km{\times}day$ (115%) and $1,985,000KRW/km{\times}day$ (119%) occurred on Sections B and D with approximately 20,000 AADT respectively and the delay cost of $262,000KRW/km{\times}day$ (105%) occurred on Section C with approximately 10,000 AADT. This result of this study was estimated based on the simulation of traffic flow model so that there is a limitation in its actual application. A study ot develop a highly appropriate model using actual observation data and improve the possibility to apply it through the verification using the simulation will be necessary in future.